HomeMy WebLinkAbout03007 - Technical Information Report - Drainage BAIMA & HOLMBERG INC.
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DRAINAGE REPORT
for
Nick's Short Plat
April 28,2003
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E�PIRES 11/30/04
Baima & Holmberg, Inc. Job No. 2016-042
Prepared For
Pat Anardi
PO Box 58233
Renton, WA 98058-1233
w 3�o�
�, 100 FRONT STREET SOUTH • ISSAQUAH • WASHINGTON • 98027-3817 • (425) 392-0250 • (425)391-3055
Project Overview
This project involves the short platting of a 0.35-acre parcel into 3 single-family
lots. The site is located on the west side of Morris Avenue South between South
15th Street and South 17th Street. The site currently has a house, garage, driveway
and lawn. The site slopes down to the north at about 5%.
Downstream Drainage
This site is in a part of town that has very little drainage improvements. The frant
yard of the e�sting site drains east to the paved roadway, collecting in an asphalt �I
gutter along the west side of the street. This gutter drains north about 400' where ,
it is collected into a catch basin at the intersection of 15�' and Moms. An 8"
storm pipe flows east from the catch basin about 150' to another catch basin ,
where a 12" pipe turns north along the west side of Morris, eventually flowing
north to a large diameter culvert crossing I-405, about '/a mile downstream of the
site. There are no obvious drainage problems along this drainageway.
The majority of the site sheet flows north across the neighboring property,
crossing several lots. It does not appear that this runoffis ever picked up with any
sort of storm system. It presumably soaks into the ground before reaching South
15th Street, about 400' north of the site.
___
_
Drainage Control �`��- -- --
_ __--------
----- _�
-�, Because the only drainage conveyance system is the existing gutter in Morris
Avenue 5outh, the proposed onsite drainage control consists of dispersing roof
runoff at splash blocks from the new houses and allowing it to flow into the gutter
of the proposed onsite, private roadway. The proposed private roadway is graded
to pick up all onsite runoff and direct it into the eausting gutter along the west side
of Morris. Per exemptions in the 1990 KCSWDM Core Requirement#3,
detention and water quality controls are not required for this project.
�
i—J
1990 KC SWDM Core Requirements
Section 1.2.1 Core Requirement #1: Discharge at the Natural Location
• The site drainage will discharge to the e�sting drainage system discharge
point, to the catch basin and�ipe storm system at the corner of Morris
Avenue South and South 15 Street. Because there is no storm system
e�ending to this site, the onsite private roadway wili be graded to drain the
site into the existing gutter on Moms, which flows to the aforementioned
storm system.
Section 1.2.2 Core Requirement #2: Offsite Analysis
• An offsite drainage analysis is provided in this report.
Section 1.2.3 Core Requirement#3: Runoi'f Control
• Because the increase in 100-yr peak flow for developed vs. e�sting conditions
is less than O.Scfs, detention is not required on this project. Because the new
impervious area subject to vehicular use is less than 5000 sq-ft, water quality
measures are not required.
Section 1.2.4 Core Requirement#4: Conveyance System
• The conveyance consists of a gutter for small flows from this small project.
Therefore analysis is not needed..
Section 1Z.5 Core Requirement#5: Erosion/Sediment Control Plan
• A temporary erosion control plan provides BMP's to be implemented during
construction.
Section 1.2.6 Core Requirement#6: Maintenance and Operation
• A maintenance and operations manual is provided in the TIR.
Section 1.2.7 Core Requirement#7: Bonds and Liability
• The developer will arrange for any financial guarantees and liabilities required
by the pernut.
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BAIMA & HOLMBERG, INC. SHEETNO. OF
100 Front Steet South
ISSAQUAH, WASHINGTON 98027-3817 �CULATEDBY T�L DATE
(425) 392-0250 FAX (425) 391-3055
CHECKED BY DATE
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BAIMA & HOLMBERG, INC. S,,E��,,o o�
100 Front Steet South
ISSAQUAH, WASHINGTON 98027-3817 CALCULATEDBY �� DATE �
(425) 392-0250 FAX (425) 391-3055
CHECKED BY DATE
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Existing Conditions SBUH 100-yr Peaks
******************** S.C.S. TYPE-lA DISTRIBUTION **********;;*;**+**{
********* 100-YEAR 24-HOUR STORM **** 3.90" TOTAL PRECIP. *;*******
DATA PRINT-OUT:
AREA(ACRES) PERVIOti: ID:PER'JIOUS TC (I�IIi�IUTES,'
A CN A CN
.4 .3 86.0 . l 95. 0 5. 0
PEAK-Q{CFS) T-PEAK(HRS} VOL{CU-FT}
.26 7.67 3374
Developed Conditions SBUH 100-yr Peaks
-------------------------------—----------------------------------
******************** S.C.S. TYPE-lA DISTRIBUTION ********************
********* 100-YEAR 24-HOUR STORM **** 3.90" TOTAL PRECIP. *********
----------------------------------------------------------------------
DATA PRINT-OUT:
AREA(ACRES) PERVIOUS IMPERVIOUS TC(MINUTES)
A CN A CN
.4 .2 86.0 .2 98.0 5.0
PEAK-Q(CFS) T-PEAK(HRS) VOL(CU-FT)
.30 7.67 3910
IkING COUNTY, �VASHINGTON, SURFACE W ATER DESIGN MANUAL
KING COUNT'Y, WASHINGTON
SURFACE WATER DESIGN MANUAL
APPENDIX A
MAINTENANCE REQUIREMENTS
FOR PRIVATELY MAINTAINED
DRAINAGE FACILITIES
Section No. Subject
1 Ponds
2 Infiltratton
3 Closed Detention Systems i
4 Control StructurelFlow Resthctor ,
5 Catch Bastns '
6 Debris Barriers
7 Energy Dissapators
8 Fencing
9 Gates
10 Conveyance Systems
11 Grounds
12 Access Roads/Easements
1/90
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
MAINTENANCE REQUIREMENTS FOR
PRIVATELY MAINTAINED DRAINAGE FACILITIES
NO. 1 - PONDS
Maintenance Con�tio�a When Maintensnce Results Expected When
Component Detect b Needed Meintenance b Pevformed
General Trash&Debrie Any trash end debris which exceed 1 cubic Trash end dabria cleered from
foot per 1,000 squaro feet (this is ebout equel site.
to the amount of trash it would take to fill up
one stendard size office garbage can). In
peneral,there should be�o visud evidence of
dumpine.
Poisonous Any pasonous veqetetion which may No danper of poieo�ous
Vepetetion consdtute a hazerd to County penonnel or the vegetation whero County
puWia Examples of poisonous vegetedon personnel or the public mipht
include: tensy reywort,pason oak,atinginy �ormally be. (Coordination with
nettles,devils club. Seattle/iGng County Health
DepartrnenU
Polludon 0�,pesoFne,or other contaminants of one No contamina�ts present othe�
pallon or mors o►a�y emount found that then e aurface film. (Coordination
could: 1) cause damage to ple�t, ariimal,or with Seattle/King County Health
mari�e Gfe; 2)constitute e fire hazard;o� Depertment)
3)be flushed downstroem durinp rain atortns.
Unmowed Gress! If faciGty is located in private residentiel area, When mowinp is needed,
Ground Cover mowiny is needed when prass exceeds 18 prass/ground cover ahould be
inches in heipht: In other ereas,the ganerel mowad to 2 i�ches in heiyht.
policy is to make the pond site match adjacent
. prou�d cover and terrain es lonp es tfiere is tw
. interference with the funcUon of the facility.
Rodent Hdes Any evidence of rodent holes if fecility is Rodents destroyed snd dam or
actinp as a dem or berm, or s�y evidence of berm repeired. (Coordi�ation with
water pipiny tFuouph dam or berm via rode�t Seattle/Ki�g County Health
holes. Department)
. Insects When insects such as wasps and hornets Insects destroyed o�removed
inte�fero with meintenance ectivities. from site.
Tree Growth Tree p�owth does not ellow meintenance Trees do not hinder mei�tenance
access or interferas with mainta�ance ectivity ectivities. Selactively cultivate
• G.e.,slope mowing, silt removel,vactoring, or trees such as ddars for firewood.
squipment movemants). If trees are not
_ interfaring with access,leava trees alone.
Side Slopes of E�osion Eroded demage over 2 inches deep where Slopes should be stabilized by
Pond ceuse of damage is still prosent or where usi�p appropriate eroaion control
there is potentiel for continuad erosion. measure(s);e.fl., rock
ranforcement, planting of prass,
compaction.
Storepa Araa Sediment Accumulatad aediment that excsada 10%of Sediment cleaned out to dasig�ed
the designed pond depth. porxi shepe end depth;pond
reseeded if necessary to control
erosion.
Pond Dikes Settlements Any part of dike whicti has settled 4 inches Dike should be built beck to the
lower than the desipn elevation. desien elevation.
, Emergancy Rock Missing Only one layer of rock e�dsts ebove native soil Replace rocks to dasig� .
Overflow/Spillway in are five square feet or larper,or e�y standa�ds.
exposure of native soil.
� A-1 11/94
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
NO. 2 - INFILTRATION
Meintenanc� Co�dittons Wh�n Meint�nana Resulta Ezpected When
Component Defoct k Needed Mei�tenance Is Performed
Generai Trash&Debris See"Ponds"Stendard Na. 1 See"Ponds"Stenderd No. 1
Poisonous See'Ponde" Stenderd No. 1 See"Ponds" Stenderd No. 1
Vegetetion
Pollution See'Ponde" Standard No. 1 See"Ponds"Stendard No. 1
Unmowed Grese/ See'Ponde"Stendard No. 1 See"Ponde'Standerd No. 1
Ground Cover
Rodent Holes Sea'Ponds" Stenderd No. t See"Ponda'Stenderd No. 1
Insects See'Ponde' Stendard No. 1 See"Ponds"Standerd No. 1
Storepe A�ea Sediment A percolation test pit or test of facility Sedime�t ie removed and/or
indicatas facility�s o�ly workinq at 90%of its facility is cleaned so that
desipoed cepabilities. If two inches or more infiltration�ystem worlcs
sediment is present, remove. accordinQ to desipn.
Shaet Cove�(If Sheet covar is visible and hes mors that tFxee Sheet cover�eparsd or repleced.
Appliceble) 1/4inch holas in it.
Sump FAled with Any sedimenf erx�dabris fillinq vault to 10% Geen out sump to desipn depth.
Sedmiment and of depthfrom.sump bottom to bottom of
Debria(If Applicable) oudet pipe or obstrucfinp flow into tfie
coru�ector pipe.
Fdter Baps Filled with Sediment and debris fill bap mo�e then 1/2 Replace filter bay or redesiqn
Sedmiment and tuA. systam.
Debris
Rock Filters Sedime�t and Debris By visual inspectipn,tiftle or no water flows Replace prevel in rock filter.
throuph filter durinp Mavy rain storms.
Side Slopes of Erosion Sea'Ponds'Standard No. 1 See"Ponds"Standard No. 1
Pond
Emerger►cy Rock WGssing See"Ponds'Standerd No. 1
Overflow Spillway
Settlinp Ponds and Sediment Remove when 6"o�more.
Vaults
Note: Sediment accumuletion of more than .25 fnches per year mey indicete excessiva erosion is occu�ring upetream of tfie facility or
that conveyance systems are not beinq properly maintainad. The contributinq dreinage area�hould be checked tor eroaio�problems •
or i�edequete meintenence of conveyance cystems if excessivo sedimentation is�oted in en i�flltraGo�fecility.
Check twice a yeer during first 2 yearo of operadon;once a yea�theroaher. pean manholeslcetch baeins,repai�demaged
inlets/outlets, dean tresh recks. '
� A-2 11/94
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
NO. 3 - CLOSED DETENTION SYSTEMS (PIPES/TANKS)
Maintenance CondiUons When Malntenance Resuks Expected
Component Defect is Needed YVhen Malntenance is Periormed
Storage Area Plugged Air Vents One-hatt of the cross section of a vent is Vents free of debris and sediment.
blocked at any point with debris and
sediment.
Debris and Accumulated sediment depth exceeds All sediment and debris removed from
Sediment 10%of the diameter of the storage area storage area.
for 1/2 length of storage vault or any
point depth exceeds 1596 of diameter.
Example: 72-inch storage tank would
requi�e cleaning when sediment reaches
depth ot 7 inches tor more than 1/2
length of tank.
Joints Between My crack ailowing material to be AI�Joints between tank/pipe sections are
Tank/Pipe Section transported into faality. seaied.
Tank/Pipe Bent My part of tank/piPe 1s bent out of shape Tank/pipe repaired or replaced to design.
Out of Shape more than 10%of its design shape.
Manhote Cover not in Place Cover is missing or o�ly partialty in place. Manhole is closed.
� My open manhole requires maintenance.
Locking Mechanism cannot be opened by one Mechanism opens with proper tools.
Mechanism,Not maintenance person with proper tools.
Working Bolts into frame have less than 1/2 inch •
of thread (may not apply to seH-locking
lids).
Cover Difficuk to One maintenance psrson cannot remove Cover can be removed and reinstalled by
Remove � lid after applying 80 pounds of lift. Intent one maintenance person.
is to keep cover from sealing off acxess
to maintena�ce.
Ladder Rungs iGng County Safety Offioe and/or Ladder meets design standards and
Unsafe maintenance person judges thatladder is allows maintenance persons safe axess. '
unsafe due to missing rungs,
misalignment,rust,or cxacks.
Catch Basins See'Catch Basins'$tandard No.5 See'Catch Basins'Standard No.5
A-3 1/�9�
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
NO. 4 - CONTROL STRUCTURE/FLOW RESTRICTOR
Maintenance CondtBons VYhen Malotenance Resutts Expected
Component De(ect is Needed When Matntenance is Performed
General Trash and Debris Distance between debris buiid-up and All trash a�d debris removed.
(Inciudes bottom of orifice plate is less than 1-i/2
Sediment) feet. •
Structural Damage Structure is not securely attached to Structure securely attached to wall and
manhole wall and outlet pipe structure outlet pipe.
should support at least 1,000 pounds of
up or down pressure.
Structure is not in upright position (atlow Structure in correct position.
up to 10%from plumb).
Connections to outl�t pipe are not Connections to ouilet pipe are watertight;
watertight and shovr signs of rust. � structuro repaired or replaced and wo�ics
as designed.
My holes—other than desig�ed hoies— Structure has no holes other than
. in the structure. - designed holes.
Cleanout Gate Damaged or peanout gate is not watertight or is Gate is watertight end works as designed.
Missing missing.
Gate canr►ot be moved up and dovm by Gate moves_up and down easily and is
one mai�tenance person. watertight.
Chai�leading to gate is missing or Chain is in place a�d works ss designed.
damaged.
Gate is rusted ovo�50%of its surfaoe Gate is repaired or replaced to meet '
. area. design standards.
Oritice Plate Damaged or ConVol device is not worfcinp propetly Plate is in place end works ns dosiened.
Missing due to missing,out ot place,or beM
orifice plate.
Obstructions Any trash,debris,se�iiment,or vegetatio� Plate is lree of all obsVuctions and works
blodcing the plate: as designed.
Overflow Pipe Obstructions My trash or debris blocfcing (or having Rpe is free of all obstructions and works
the pote�tial of blodcing)the ovefiow as designed.
P�PB• ,
Ma�hole See'qosed Detentlon Systems'Standard 'Ses'posed Detention Systems'Standard
No.3. No.3.
Catch Basin See'Catch Basins'Standard No.5. See"Catch Basins"Standard No.5.
A-4 1/90
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
NO. 5 - CATCH BASINS
Maintenance Conditions YVhen Maintenance Resuks Expected II
Component Defect is Needed When Malntenance is Performed
General Trash&Debris Trash or debris of more than 1/2 cubic No Vash or debris located immediately i� III
(Includes toot which is located immediately in front front of catch basin opening. '
Sediment) ot the catch basin opening or is blocking • I
capacity ot basin by more than 10%. ,
Trash or debris (n the basin)that No trash or debris in the catch basin. '
exceeds 1/3 the depth from the bottom '
of basin to invert of the lowest pipe into
or out of the basin.
Trash ocdebris'in any inlet or ouUet pipe Inlet and outlet pipes free of lrash or '
blocking more than t/3 of its height. debris. ,
Dead animals or vegetation that could No dead animals or vegetation present
generate odors that would cause within the catch basin. �,
complaiMs or dangerous gases_(e.g., �
methane).
Deposits of garbage exceeding 1 cubic No condition present which would attract �I
foot in volume. or suppoR the breeding ot insects or
rodents. �
Structural Damage Comer of frame extends more than 3/4 Frame is even with curb. I
to Frame and/or inch past curb face into the street (rf �
Top Siab applicable). .
Top slab has holes larger than 2 square Top slab is free of holes and cracks.
inches or cxacks wider than 1/4 inch
(intent is to make sure all material is
running into the basin).
Frame not sitti�g flush on top slab,i.e., Frame is sitting flush on top slab.
i separation of more than 3/4 inch oi the
irame hom the top slab.
Gacks in Basin . Gacks wider than 1�2 inch and bnger Basin replaced or repaired to design
Walls/Bottom than 3 feet,any evi ence of soil particles standards.
entering catch basin through cracks,or
maintenance person judges that structure
is unsound.
Gadcs wider than 1/2 inch and bnger No aacks more than 1/4 inch wide at the
than 1 toot at the joint of any inlet/outlet joint of inlet/outlet plpe.
pipe or any evidence of soil parGcles
entering catch basin through cracks.
Settlement/ Basin has setUed more than 1 inch or has Basin replaced or repaired to design
Misalignment rotated more than 2 inches out of standards.
alignment.
Fre Hazard Presence of chemicals such as natural No flammable chemicals present.
gas,oil,and gasoline.
Vegetation Vegelation growing acxoss and blocking No vegetation blocking opening to basin.
more than 1096 of the basin opening.
Vegetation growing in inlet/ouUet pipe No vegetation or root growth present.
joints that is more than six inches tall and
less than six inches apart.
Pollution Nonflammable chemicals of more than No pollution present other than surface
1/2 cubic foot per three feet of basin film.
length.
A-5 1/'9� :
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
NO. 5 - CATCH BASINS (Continued)
Maintenance Condtt{ons VYhen Mslntenance Resuka Expected
Component Detsct is Needed 1Nhen Malntenence Is Perfo�med
Catch Basin Cover Cover Not in Plaoe Cover is missing or ony partially in place. Catch basin cover is closed.
My open catch basin requires
maintenance.
Locking Mechanism cannot be opened by one Mechanism opens with proper tools.
Mechanism Not malntenance person'with proper tools.
Working Bolts into frame have less than 1/2 inch
ot thread.
Cover Difficult to One maintenance person ca�not remove Cover can be removed by one
Remove lid after applying$0 Ibs.oi lift; intent is maintenance person.
keep cover irom seali�g off access to
mai�tenance.
� Ladder tadder Rungs Ladder is unsafe due to missing rungs, Lddder meets design standards and
U�safe misalignment,rust,cxadcs,or sharp olows maintenance person safe acxess.
, edges. I
. Metal Grates Grate with opening wider than 7/8 inch. Grate openin8s meet design standards.
(if applicable)
Trash and Debris Trash cnd debris thai is blocking moro G�ate free oi trash and debris.
tlian 2096 ot grate surface. I
Damaged or Cxate missing or broken member(s}ot Grate is in place and meets design I
Missing the grate. standards. �
A-6 1/90
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
NO. 6 - DEBRIS BARRIERS (e.g. Trash Racks)
Maintenance CondiUons When Malnte�ancs Reautts Expectod
Component Defect Is Needed YVhen Maintenance Is Performed
General Trash and Debris Trash or debris that is plugging more Barrier clear to receive capaaty fiow.
than 20%oi the openings in the barrier.
Metal Damaged/Missing Bars are bent out of shape more than 3 Bars in place with no bends more than
Bars inches. 3/4 inch.
Bars are missing or entire barrier is Bars in place according to design.
missing.
Bars are loose and rust is causing 50% Repair or replace barrier to design
deterioration to any part of barrier. standards.
_ -- -- - —----- - __ _ �
A-7 1��
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
NO. 7 - ENERGY DISSIPATORS
Maintenance Conditlo�s When Maintenanco Resutts Expected
Component Delect Is Needed When Malntanance Is Performad
Euternal:
Rock Pad Missing or Moved Only one layer of rock exists above native Replace rocks to design standard.
Rocic soil in area five square teet or larger,or
any exposure oi native soil.
Dispersion Trench Pipe Pougged with Accumulated sediment that exceeds 20% Pipe cleaned/fiushed so that it matches
Sediment of the design depth, dssign.
Not Discharging Visual evidence of water discharging at Trench must be redesigned or rebuilt to
Water Properly concentrated points along trench (normal standard.
condi6on is a'sheet flow"of water along
trench). Intent is to prevent e�osion
damage.
Perforations Over 1/2 of perforations in pipe are Gean or repiace perforated ppe.
Plugged plugged with debris'and sediment
Water Flows Out Malntenance person observes water Facility must be rebuilt or redesigned to
Top of"Distributor" flowing out during any storm less than standards:
Catch Basin the design storm or it is causing or
appears likely to cause damage.
: Receiving Area Water in receiving area is causing or has No danger of landslides.
� Over-Saturated potential of causing landslide problems.
Infemal:
Manhole/Chamber Wom or Damaged Shucture dissipating flow deteriorates to Replace structure to design standards.
Posts,Baffles, 1/2 or original size or any concentrated
Sides of Chamber worn spot exceeding one square foot
which would make structure unsound.
Other Defects See"Catch Basins"Standard No.5 See'Catch Basins'Standard No.5
�
A-8 1/90
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
NO. 8 - FENCING
Malntenance Conditlons When Maintenance ResuRs Expected
Component Defect is Needed YYhen Malntenance is Performed
General Missing or&oken Ar►y defect in the tence that permits easy Parts in place to provide adequate
Parts entry to a facility. securiry.
Parts broken or missing. &oken or missing parts replaced.
EroSion Erosion more than 4 inches high and 12- No opening under the fence that exceeds
18 inches wide permitting an opening 4 inches in height.
under a fence.
Wire Fences Damaged Parts Posts out of plumb more than 6 inches. Posts plumb to within t-1/2 inches.
Top rails bent more than 6 inches. Top rail iree of bends greater than 1 inch.
My part of fence (ncluding posts,top Fence is aligned and meets design
rails,and fabric)more than 1 foot out of standards.
design alignment
Missing or loosa tension wire. Tension wire in place a�d holding fabric.
Missing or loose barbed wire that is Barbed wire in place with less than 3/4
sagging more than 2-1/2 inches between inch sag between posts. ,
Posts•
Extension arm missing,broken,w bent Extension arm in place with no bends
out of shape more than t-1/2 inches. larger than 3/4 inch.
Deteriorated Paint Part or parts that haye a rusting or scaling Structurally adequate posts or parts with
w Protective condition that has affected structural a uniform protective coating.
Coating adequacy.
Openings in Fabric Openings in fabric are such that an 8- No openings in fabric.
inch�iameter ball could fit through.
A-9 1/'90
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
NO. 9 - GATES
Maintenance Co�dlUons When Malntenance Resuits Expected
Component Defect is Needed Whon Maintenance Is Performed
� General Damaged or Missing gate or locking devices. Gates and lodcing devices in place.
Missing Membe�s
. Broken or missing hinges such that gate Hinges intact and lubed. Gate is working
cannot be easily opened and dosed by a ireely.
maintenance person.
Gate is out of ptumb more than 6 inches Gate is aligned and vertical.
and more than 1 foot out of design
alignment.
Missing stretchar bar,sVetcher bands, Stretcher bar,6ands,and ties in place.
• and ties.
Openings in Fabric See"Fenang'Standard No.8 See"Fencing"Standard No.8
A-10 1/90
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
. NO. 10 - CONVEYANCE SYSTEMS (Pipes & Ditches) '
Maintenance Conditlons When Malntenance ResuRs Expected �
Component Defect Is Needed VYhen Malntenance Is Performed I
Pipes Sediment�Debris Accumulated sediment that exceeds 2096 Pipe cleaned of all sediment and debris. �
of the diameter of the pipe. j
Vegetation Vegetation that reduces free movement of All vegetation removed so water flows
water through pipes. freely through pipes. '
Damaged Protective coating is damaged; rust is Pipe repaired or replaced. ,
causing more than 50%deterioration to
any part of pipe. ,
My dent that decreases the cross section Pipe repaired o�replaced.
area of pipe by mora than 2U%.
Open Ditches Trash&Debris Trash and debris exceeds 1 cubic foot Trash and debris deared irom ditches.
per 1,000 square feet of ditch and slopes. I
Sediment Aacumulated sediment lhat exceeds 2096 Ditch deaned/flushed of all sediment and i
. of the design depth. debris so that it matches design. �
Vegefation Vegetation that reduces hee movement of Water flows ireely through ditches. I
wate�through ditches.
� Erosion Damage to See'Ponds'Sta�daud No.1 See'Ponds'Standard No. 1 ��
Slopes '
Rock Lining Out of Maintenance person can see native soii Reptace rodcs to design standard.
Place or Missing (If beneath the rock lining. ,
Appiicable) '
Catch Basins See'Catch Basins'Standard No:5 See`Catch Basins'Standard No.5
Debris Barriers See"Debris Barriers'Standard No,6 See'Debris Barriers'Standard No.6
(e.g.,Trash Rack)
A-11 1/90
I
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
NO. 11 - GROUNDS (Landscaping)
Maintenance Cond(Uons When Malnte�a�ce Rewtts Expsctsd
Compo�ent Defect Is Needed VYh�n Malnt�nanc�It P��formed
General Weeds Weeds growing in mora than 2096 of the Weeds present tn less than 5%of the
(Nonpoisonous) landscaped area (trees and shrubs only). landscaped area.
Safety Hazard My presence of poison ivy o�other No poisonous vegetation present in a
poisonous vegetation. landscaped area.
Trash or l�tter Paper,can,bottles,totalling more than 1 Area dear of litter.
cubic foot within a landscaped area (Vees
and shrubs only)of 1,000 square teet.
Trees and Shrubs Damage l3mbs or parts oi trees or ahrubs that are Treas end shrubs with less than 5%of the
split or broken which effect more than total toliage with split or broken limbs.
25%ot the total foiiage of the tree or
sh�ub.
Trees or shrubs that have been blown Trse or shrub in piace lree oi injury.
� down or knocked ova�.
Trees or thrubs which ere not edequately Trse or shrub in place and adequately
supported o�eue leaning over,causing suppo�ted;romove eny dead or diseased
exposure of the roots. trees.
f
A-12 �/N
KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL
NO. 12 - ACCESS ROADS/EASEMENTS
Maintenance Condittons Whe� Maintenance � ResuRs Expected
Component Defect is Needed When Maintenance is Pertormed
General Trash and Debris Trash and debris exceeds 1 cubic foot Trash and debris deared from site.
per 1,000 square feet,i.e.,trash and
debris would fill up one standard size
garbage can.
Blocked Roadway Debris which could damage vehicle tires Roadway free of debris which could
(glass or metal). damage tires.
My obstructions which reduce clearanoe Roadway ovefiead clear to 14 teet high.
above road surface to less than 14 feet.
, My obstructions resVicting the access to Obstruction removed to allow at least a
a 10-to 12-ioot width tor a distance of 12-foot access.
more than 12 feet or arty point restricting
access to less than a 10-foot width.
Road Surtace Settlement, When any surface defect exceeds 6 Road suriace unifo�mty smooth with no
Potholes,Mush inches in depth and 6 square ieet in area. evidence of settlement,potholes,mush
Spots, Ruts In general,any surface defect which spots,or ruts.
- hinders or prevents maintenance acxess. �
Vegetation in Road Weeds growing in the road surface that Road surface free of weeds taller than 2
Surface are more than 6 inches tall and less than inches.
6 inches apart within a 400-square-foot
area.
Shoulders and Erosion Damage Erosion within 1 foot of the roadway more 5houlder free of erosion and matching
Ditches than 8 inches wide and 6 inches deep. the sunounding road.
Weeds and&ush Weeds and brush exceed 18 inches in Weeds and btush cut to 2 inches in
height or hinder maintenanc:e access. height or deared in such a way as �.:
allow maintenance access.
A-13 1��